National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KDMX 152045
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
345 PM CDT SAT JUN 15 2013

.SHORT TERM.../TONIGHT /...
ISSUED AT 345 PM CDT SAT JUN 15 2013

WATER VAPOR IMAGERY SHOWS WELL DEFINED AXIS OF WEAK SHORT WAVES FROM
KS INTO MN WITH NOTED SUBSIDENCE AND FORCING ON EITHER SIDE.  ONE
OF IMMEDIATE CONCERN IS NEAR THE NE/IA/KS/MO BORDER AND IS CURRENTLY
PRODUCING WEAK ELEVATED CONVECTION.  RECENT RADAR LOOP SUGGESTS THIS
CLUSTER IS STEADY STATE...HOWEVER IT IS MOVING INTO A SOMEWHAT MORE
FAVORABLE ENVIRONMENT.  RAP2 MLCAPE ANALYSIS SHOWS UNCAPPED 2-3K
J/KG DOWNSTREAM WITH 30-40 KTS OF EFFECTIVE SHEAR...MORE THAN ENOUGH
FOR SUPERCELLS IF CONVECTION HAPPENS TO STRENGTHEN AND BECOME ROOTED
LOWER.  MAIN THREATS WOULD BE LARGE HAIL AND DAMAGING WIND...IF IT
HAPPENS TO ORGANIZE.  MEAN WIND...SUPERCELL STORM MOTION AND
FORWARD PROPAGATING CORFIDI VECTORS SUGGEST OK/KS/MO CONVECTION WILL
TAKE A RIGHT TURN AND NOT AFFECT FORECAST AREA.

WILL CANCEL NRN PORTION OF FLASH FLOOD WATCH NEAR AND BEHIND
SYNOPTIC SUBSIDENCE AND WEAK BOUNDARY NOTED WHERE RAP2 MLCINH IS
QUITE STRONG.  CENTRAL AND SRN SECTIONS WILL BE LEFT INTACT.  IF
COMPLEX HAPPENS TO INTENSIFY...PWATS WILL STILL BE 1.5 TO JUST UNDER
2 INCHES WITH INCREASING WARM CLOUD DEPTHS.  MOISTURE TRANSPORT WILL
BE VEERING HOWEVER SO THREAT SHOULD NOT LAST TOO LONG BEYOND
00Z...IF AT ALL.

SKIES SHOULD GRADUALLY CLEAR OVERNIGHT AND WITH DIMINISHING WINDS
AND WET SOILS FOG WILL BE SOMEWHAT OF A CONCERN.  HAVE NOT
INTRODUCED INTO THE PUBLIC FORECAST AS OF YET WITH NW WINDS
APPEARING JUST STRONG ENOUGH FOR SIGNIFICANT REDUCTIONS...HOWEVER
THESE TRENDS WILL HAVE TO BE MONITORED.

.LONG TERM.../SUNDAY THROUGH SATURDAY/...
ISSUED AT 345 PM CDT SAT JUN 15 2013

FAST NEAR ZONAL/NORTHWEST FLOW PATTERN ALOFT...WITH SHORTWAVE
EMBEDDED IN THE FLOW TO MOVE THROUGH NE/IA/MO TOWARD LATE SUNDAY
AFTERNOON INTO SUNDAY EVENING. MOISTURE ADVECTION TO NOSE INTO THE
FAR WEST CENTRAL/SOUTHWESTERN CWA SUNDAY AFTERNOON INTO THE
OVERNIGHT HOURS SUNDAY NIGHT. NAM SOUNDINGS INDICATE
SOUTHWESTERN/WEST CENTRAL CWA BECOMING UNCAPPED BY 21Z INTO EARLY
EVENING. THEREFORE HAVE INCREASING CHANCES OF THUNDER ACROSS THE
WEST/SOUTHWEST STARTING AROUND 21Z WITH CHANCES FOR THUNDER
POSSIBLE ACROSS ENTIRE CWA BY LATE IN THE EVENING/OVERNIGHT HOURS.
MAY HAVE SOME LINGERING ACTIVITY INITIALLY BY EARLY
MONDAY...OTHERWISE WEAK FRONTAL BOUNDARY EXPECTED TO BE IN PLACE
ACROSS THE SOUTHERN CWA. COULD SEE SOME REDEVELOPMENT MONDAY
AFTERNOON ACROSS THE SOUTH. HOWEVER BETTER CHANCES WILL BE IN
MISSOURI CLOSER TO THE UPPER LEVEL SHORTWAVE. HAVE KEPT TUESDAY
DRY FOR NOW...BUT WILL HAVE TO MONITOR AS THE EC STARTING TO
ADVERTISE A WEAK SHORTWAVE DROPPING THROUGH EASTERN IOWA. IF WOULD
HAVE SOME PRECIP WITH THIS WAVE...CHANCES WOULD BE ACROSS THE FAR
EASTERN CWA...WITH BETTER CHANCES TO THE NORTH/EAST OF THE CWA.
OTHERWISE UPPER RIDGING TO SHIFT EAST SLIGHTLY WITH HIGH PRESSURE
DOMINATING THE REGION...SUGGESTING DRY CONDITIONS FOR THE MIDWEEK
TIME PERIOD.

THE UPPER RIDGING BEGINS TO FLATTEN TOWARD THE LATTER HALF OF THE
WEEK INTO THE WEEKEND...WITH AN UPPER LOW DIGGING ONSHORE OVER THE
NORTHERN ROCKIES TOWARD THURSDAY NIGHT INTO FRIDAY. ENERGY EJECTING
OUT OF THE WEST COAST TROUGH AND TRAVELING THROUGH THE UPPER RIDGE
ACROSS THE CENTRAL US WILL BRING A RETURN OF PRECIPITATION CHANCES
FOR THE LATTER HALF OF THE WEEK INTO THE WEEKEND. BEST CHANCES
APPEAR TO BE FRIDAY NIGHT THROUGH SATURDAY NIGHT...AS SFC LOW AND
ASSOCIATED INVERTED TROUGH AXIS STRETCHED ACROSS THE CWA. LOOKS LIKE
A NEAR REPLICA OF THE PAST 24 HOURS...WITH ACTIVITY EXPECTED TO
DEVELOP FRIDAY AFTERNOON DEVELOPING INTO AN MCS FRIDAY NIGHT...AND
REDEVELOPMENT/ONGOING ACTIVITY FOR SATURDAY.

REGARDING TEMPERATURES...WITH MID TEENS CELSIUS ALOFT THROUGHOUT THE
PERIOD SHOULD CONTINUE TO SEE HIGHS IN THE UPPER 70S TO LOWER 80S
THROUGHOUT THE NEXT WEEK.


&&

.AVIATION...15/18Z
ISSUED AT 1253 PM CDT SAT JUN 15 2013

SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO AFFECT SITES
INTO AT LEAST THE EARLY EVENING. CONDITIONS WILL MAINLY BE VFR
OUTSIDE OF HEAVIER STORMS...WHICH APPEAR TO BE ISOLATED AT THE
MOMENT. GENERAL TREND IS FOR CONVECTION TO GRADUALLY PUSH OFF TO
THE SOUTH AND EAST THROUGH THE AFTERNOON AND EVENING...ENDING AT
KFOD BY 23Z AND KOTM BY 05Z. OUTSIDE OF PRECIP IMMEDIATELY
AFFECTING SITES...HAVE GENERIC VCSH WORDING UNTIL TRENDS AND
TIMING BECOME MORE CLEAR. SOME CONCERN THAT FOG MAY ALSO DEVELOP
OVERNIGHT AS WELL. MOS GUIDANCE IS NOT TOO BULLISH BUT WITH RECENT
RAINS...CLEARING SKIES AND WINDS BECOMING LIGHT HAVE ADDED MVFR
MENTION IN SOME LOCATIONS FOR A START.


&&

.DMX WATCHES/WARNINGS/ADVISORIES...

FLASH FLOOD WATCH UNTIL 7 PMCDT THIS EVENING FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BLACK HAWK-BOONE-BREMER-BUTLER-CALHOUN-CARROLL-
CASS-CLARKE-CRAWFORD-DALLAS-DAVIS-DECATUR-FRANKLIN-GREENE-GRUNDY-
GUTHRIE-HAMILTON-HARDIN-HUMBOLDT-JASPER-LUCAS-MADISON-MAHASKA-
MARION-MARSHALL-MONROE-POLK-POWESHIEK-RINGGOLD-SAC-STORY-TAMA-
TAYLOR-UNION-WAPELLO-WARREN-WAYNE-WEBSTER-WRIGHT.

&&

$$

SHORT TERM...SMALL
LONG TERM...BEERENDS
AVIATION...SMALL